Advancements in the science of biomaterials have been slow due in part to the lack of model materials with stepwise-variable surface composition. Furthermore, the ability to systematically control polymer surface chemistry would have great practical utility in the (empirical) development of new biomaterials for tissue engineering and for use in ex vivo and in vivo devices and prostheses. Our preliminary work suggests that while rates are significantly lower, equilibrium surface tension/composition of polymer blends is quantitatively similar to conventional liquid surfactants in liquid solvents. Surface energy minimization drives the process of surface equilibration which depends on the nature of the interface, e.g., air versus blood. The proposed study would measure the efficiency and effectiveness of novel surface-active solid polymers (with surface-modifying oligomeric end groups), in a model base polymer. The hypothesis to be tested is that amorphous or semi-crystalline polymers are 'liquids in slow motion' with regard to surface chemistry versus bulk composition. A positive outcome would explain time-dependent changes in polymer surface composition following processing or a change in environment. Verification of the similarities between solid/solid polymer blends and liquid/liquid blends would provide a foundation for problem solving in a wide range of polymer applications involving control of surface chemistry. The results of Phase I will be used during Phase H to develop commercial process for polymer surface modification that have a variety of end uses, including tubing, blood filters, blood oxygenator, blood fractionation/blood storage, and other non-medical applications. PROPOSED COMMERCIAL APPLICATIONS These polymers are particularly suitable for use in the manufacture of medical devices intended to be used in contact with blood and tissue. Examples of medical devices include catheters, vascular grafts, prosthetic heart valves, various blood pumps and artificial organs.